1. Field of the Invention
The present invention relates to a half-fitting prevention connector, and more particularly to a half-fitting prevention connector in which a half-fitted condition is positively prevented by a disengaging force (repelling force) produced between a pair of connector housings to be fittingly connected together.
The present application is based on Japanese Patent Application Nos. Hei. 11-265829 and 2000-191558, which are incorporated herein by reference.
2. Description of Related Art
Usually, various electronic equipments are mounted on a vehicle such as an automobile, and therefore, naturally, various types of male and female connectors are provided at connection ends of various wires forming wire harnesses or the like.
Generally, male and female connectors to be fittingly connected together are provided with a lock mechanism, in which when the amount of fitting of their connector housings relative to each other reaches a predetermined value, the two connector housings are locked together in a fittingly-connected condition.
When the connector housings of the male and female connectors are connected together by the lock mechanism, each of connection terminals in the male connector housing is electrically connected to a respective one of connection terminals in the female connector housing with adequate contact pressure and contact area.
However, for example, when the operating force for fitting the two connector housings together is inadequate, and when either of the connector housings or any of the connection terminals therein is defective, the connector fitting operation is sometimes finished in a half-fitted condition in which the amount of fitting of the two connector housings relative to each other fails to reach the predetermined value.
When the male and female connectors are used in such a half-fitted condition, they may be disengaged from each other because of vibrations, developing during use, and the tension of a wire harness, and this can lead to a disadvantage that the feeding of electric power is interrupted. Even if the two connectors are not disengaged from each other, there is a possibility that in the half-fitted condition, the mating connection terminals are incompletely electrically connected together, in which case the necessary electrical characteristics are not obtained, and this may lead to a disadvantage that the associated electric part is subjected to a malfunction.
Therefore, in order to prevent an accident due to a failure to notice such a half-fitted condition of the two connectors, there have been proposed various half-fitting prevention connectors in which the two connector housings are disengaged from each other when a half-fitted condition is encountered.
FIGS. 14 to 16 show one such conventional half-fitting prevention connector disclosed in Unexamined Japanese Patent Publication No. Hei. 10-50408. An elastic lock arm 6 is formed on a connector housing 3 of a connector 1 (one of a pair of connectors 1 and 2 to be fitted together in a male-female manner), and extends in a connector fitting direction, and an engagement projection 8 is formed on a lower surface of this lock arm 6 at a distal end thereof. A slider 10 is mounted on the connector housing 3, and is movable between a non-lock position, disposed close to the proximal end of the lock arm 6, and a lock position disposed close to the distal end of the lock arm 6. A pair of right and left spring members 9 and 9, urging the slider 10 toward the lock position, are mounted on the connector housing 3. A lock projection 7 is formed on the lock arm 6, and this lock projection 7 can abut against the slider 10, returned to the lock position, to limit the displacement of the slider 10 by the spring members 9 and 9.
Stopper projections 14 and an engagement portion 13 are formed on a connector housing 11 of the other connector 2. At an initial stage of the fitting operation of the pair of connectors 1 and 2, the stopper projections 14 abut against the slider 10 to push this slider 10 back toward the non-lock position against the bias of the spring members 9 and 9 until the amount of fitting of the two connectors 1 and 2 relative to each other reaches a predetermined value, as shown in FIG. 15. When the amount of fitting of the two connectors 1 and 2 relative to each other reaches the predetermined value, the abutment portion 13 retains the engagement projection 8 to lock the two connectors in a mutually-fitted condition, as shown in FIG. 16.
In the above half-fitting prevention connector, when the pair of connectors 1 and 2 are properly fitted together, the engaged condition of the lock arm 6, mounted on the one connector 1, is locked by the slider 10, returned under the influence of the spring members 9 and 9, as shown in FIG. 16. On the other hand, when the pair of connectors 1 and 2 are in a half-fitted condition, the two connectors are disengaged from each other by the resilient force of the spring members 9 and 9, transmitted through the slider 10, as shown in FIG. 15, thus preventing such a half-fitted condition from being overlooked.
FIGS. 17 to 18C show another conventional half-fitting prevention connector disclosed in Unexamined Japanese Patent Publication No. Hei. 9-55261. In this half-fitting prevention connector, a lock arm 26 is formed on a connector housing 23 of a connector 21 (one of a pair of connectors 21 and 22 to be fitted together in a male-female manner), and extends in a connector fitting direction. An engagement projection 26a is formed on an upper surface of this lock arm 26, and a pair of guide projections 26b and 26b are formed on and project laterally from opposite side edges of the lock arm 26, respectively. A single return spring 30 is mounted in a connector housing 28 of the other connector 22, and guide walls 32 are formed on this connector housing 28. When fitting the two connectors together, the return spring 30 is pressed by the engagement projection 26a to produce a disengaging force tending to disengage the two connectors from each other. During the time when the two housings 23 and 28 are fitted together and disengaged from each other, the guide walls 32 engage the guide projections 26b, respectively, to hold the lock arm 26 in a predetermined inclined condition.
In a condition shown in FIG. 18A, as the connector housing 23 of the connector 21 is inserted into the connector housing 28 of the connector 22, the guide projections 26b of the advancing lock arm 26 are caused to slide over the guide walls 32 through respective slanting front surfaces thereof at an initial stage of this fitting operation, so that the engagement projection 26a on the lock arm 26 abuts against the distal end of the return spring 30, as shown in FIG. 18B.
As a result, during the fitting operation, that is, until the amount of fitting of the two housings 23 and 28 relative to each other reaches a predetermined value, the engagement projection 26a compresses the return spring 30 to cause this spring 30 to produce the disengaging force. Therefore, if the fitting operation should be finished in a half-fitted condition, the two connectors are disengaged from each other, thus preventing this half-fitted condition from being overlooked.
Then, when the amount of fitting of the two connectors relative to each other reaches the predetermined value, the guide walls 32 allow the engagement projection 26a to be disengaged from the return spring 30 as shown in FIG. 18C, so that the disengaging force of the return spring 30 is released. During the time when the two connectors 21 and 22 are withdrawn relative to each other, the guide projections 26b pass under the guide walls 32, respectively, thereby preventing the return spring 30 from interfering with the engagement projection 26a. 
In the conventional half-fitting prevention connector shown in FIGS. 14 to 16, there are many separate parts, including the pair of spring members 9 and 9 and the slider 10, which are to be incorporated in the connector housing, and therefore the number of the component parts increases, and also the number of steps of the assembling process increases, and this has invited a problem that it is difficult to reduce the cost.
On the other hand, in the conventional half-fitting prevention connector shown in FIGS. 17 and 18, any slider, separate from the connector housing, is not used, and only one spring member is required for obtaining the disengaging force. Therefore, the number of the component parts, as well as the number of steps of the assembling process, is smaller as compared with the lock mechanism shown in FIGS. 14 to 16, and therefore the cost can be reduced.
However, when fitting the two connector housings relative to each other, it is necessary to cause the guide projections 26b of the lock arm 26 to slide respectively over the guide walls 32 formed within the housing 28 of the other connector 22, and when disengaging the two connectors from each other, it is necessary to cause the lock arm 26 to pass under the guide walls 32.
Therefore, the amount of elastic deformation of the lock arm 26 within the mating housing is large, and a space for allowing this displacement must be secured, and this has invites a problem that the connector becomes large in size. And besides, since the amount of elastic deformation of the lock arm 26 is large, the lock arm 26 is subjected to an excessive bending force, which has led to a possibility that the lock arm 26 is damaged.
It is therefore an object of the present invention to overcome the above problems and more specifically to provide a half-fitting prevention connection of a compact, inexpensive design in which a half-fitted condition is positively prevented by a disengaging force, produced between a pair of connector housings to be fittingly connected together, without increasing the number of component parts, and the connector can be positively locked to the mating connector in a mutually-fitted condition.
To achieve the above object, according to the first aspect of the present invention, there is provided a half-fitting prevention connector which comprises a pair of connector housings fittable to each other, an elastic lock arm formed on one of the connector housings, the lock arm extending in a fitting direction of the connector housings, an engagement projection formed on the lock arm, a return spring contractibly supported on the lock arm along a longitudinal direction of the lock arm, an arm guide portion disposed on the other one of connector housings, the arm guide portion causing the lock arm to deform elastically toward an outer surface of the one of the connector housings in a half-fitted condition of the connector housings, a spring abutment portion formed on the other one of connector housings, the spring abutment portion abutting against one end portion of the return spring during connector fitting operation, so that the lock arm is elastically deformed toward the outer surface of the one of the connector housings while causing the return spring to resiliently deform, thereby producing a disengaging force urging the connector housings away from each other, and an arm retaining portion disposed on the other one of connector housings, the arm retaining portion retaining the engagement projection of the lock arm to lock the connector housings when the connector housings are completely fitted to each other after an elastic deformation of the lock arm is cancelled by the arm guide portion.
In this construction, at an initial stage of the connector fitting operation, the elastic lock arm, formed on the one connector housing, is elastically deformed toward the outer surface of the housing by the arm guide portion formed on the other connector housing.
Then, when the two connectors are fitted together, with the lock arm elastically deformed toward the outer surface of the housing, the one end of the return spring, supported on the lock arm, abuts against the spring abutment portion, formed on the other connector housing, so that the return spring is resiliently deformed, and therefore the two connectors are pushed relative to each other in the fitting direction against the bias of the return spring.
When the pushing operation is stopped in this half-fitted condition, the two connectors are pushed back relative to each other in a disengaging direction, opposite to the fitting direction, by the resilient force (bias) of the return spring urging the two connectors away from each other, and therefore this half-fitted condition can be easily detected.
Then, when the amount of fitting of the two connector housings relative to each reaches a predetermined vale, so that the two connector housings are completely fitted together, the elastic deformation of the lock arm by the arm guide portion is canceled, and the lock arm is restored into its initial position where this lock arm is spaced from the outer surface of the housing.
As a result, the return spring, held on the lock arm, moves apart from the outer surface of the housing together with the lock arm, so that the one end of the return spring is disengaged from the spring abutment portion. At the same time, the engagement projection of the lock arm is retained by the arm retaining portion formed on the other connector housing, so that the two connector housings are locked to each other in a fitted condition.
Namely, any slider, separate from the connector housing, is not used, and only one spring member is required for producing the disengaging force, and therefore the number of the component parts, as well as the number of the steps of the assembling process, is reduced, and therefore the cost can be reduced.
And besides, during the connector fitting operation and the connector disengaging operation, the lock arm is elastically deformed only in the predetermined direction relative to the arm guide portion, and the amount of elastic deformation of the lock arm can be kept to a smaller value. Therefore, damage of the lock arm due to excessive deformation is suitably prevented, and besides the size of the connector will not be increased by the provision of a space for allowing the displacement of the lock arm.
According to th e second aspect of the present invention, it is preferable that the spring abutment portion projects from an elastic portion which can be elastically displaced when the spring abutment portion is pressed through the return spring toward an inside of the other one of the connector housings in a direction substantially perpendicular to the fitting direction of the connector housings.
With this construction, even if the return spring, supported on the lock arm, is brought into engagement with the spring abutment portion when the lock arm is elastically deformed toward the outer surface of the housing to thereby disengage the engagement projection from the arm retaining portion so as to cancel the fitted condition of the two connector housings, the spring abutment portion, formed on the elastic portion, can be elastically displaced toward the inside of the housing so as not to limit the retracting movement of the return spring. Therefore, during the operation for disengaging the two connector housings from each other, the return spring will not be caught by the spring abutment portion, and therefore the operating force, required for this withdrawing operation, will not increase. Therefore, the two connector housings can be easily disengaged from each other.
According to the third aspect of the present invention, it is preferable that the return spring comprises a compression coil spring wound on the lock arm.
With this construction, merely by mounting the inexpensive compression coil spring on the lock arm, this compression coil spring can be easily supported on the lock arm so as to contract along the length of this lock arm. Therefore, the assembling operation is easy, and the cost can be further reduced.
According to the fourth aspect of the present invention, it is preferable that the half-fitting prevention connector further comprises a spring fixing portion, which is formed on a proximal end portion of the lock arm, and which limits the return spring from being biased in a direction substantially perpendicular to the fitting direction of the connector housings.
With this construction, the return spring, supported on the lock arm, is prevented from shaking upon application of external vibrations and so on. And besides, even if the two connector housings are fitted together in any posture, the return spring is prevented from being displaced or biased in a direction to decrease the amount of engagement thereof with the spring abutment portion of the mating connector housing, and therefore the more positive disengaging force can be secured.
According to the fifth aspect of the present invention, it is preferable that the half-fitting prevention connector further comprises a spring relief portion located at a distal end portion of the lock arm, the spring relief portion allowing a resilient deformation of the return spring pressed by the spring abutment portion toward an outside of the one of the connector housings in a direction substantially perpendicular to the fitting direction of the connector housings.
With this construction, even if the return spring, supported on the lock arm, is brought into engagement with the spring abutment portion when the lock arm is elastically deformed toward the outer surface of the housing to thereby disengage the engagement projection from the arm retaining portion so as to cancel the fitted condition of the two connector housings, the return spring can be elastically deformed toward the outside of the housing so as not to limit the retracting movement thereof. Therefore, during the operation for disengaging the two connector housings from each other, the return spring will not be caught by the spring abutment portion, and therefore the operating force, required for this withdrawing operation, will not increase. Therefore, the two connector housings can be easily disengaged from each other.